NASA used its Kepler observatory, which orbits the Earth on a mission to find Earth-like planets, to spot the new planets, some of which may have so-called “habitable” conditions, or conditions favorable for the creation of life.

The collection of planets, spread across the universe, was the largest such collection ever discovered, NASA said.

The planets were not seen so much as calculated. Scientists on the ground study the brightness of “planet candidates,” using an analysis to determine the probability that they are real. In the case of the 1,284, scientists determined that there was a greater-than 99-percent chance that they were real.

“Planet candidates can be thought of like bread crumbs,” said Timothy Morton, a scholar at Princeton University. “If you drop a few large crumbs on the floor, you can pick them up one by one. But, if you spill a whole bag of tiny crumbs, you’re going to need a broom. This statistical analysis is our broom.”